FACET JOINTS

The causes of most Low Back Pain remain unexplained, but the contribution of facet joint injury may have been underestimated. There remains more heat than light in the debate between enthusiasts and sceptics. Clinical methods for identifying clients with injured facet joints are improving.

The causes of most Low Back Pain remain unexplained, but the contribution of facet joint injury may have been underestimated. Low Back Pain (LBP), with or without leg pain, affects most people at some time during their lives, at considerable community cost ¹. The cause of most LBP is uncertain but a recent review ² of published studies proposes that facet(zygapophysial) joint disease contributes to between 15 and 40% of LBP.

There remains more heat than light in the debate between enthusiasts and sceptics. Although there is a sound pathological basis for the concept ^{1,
3}, clinical identification is difficult and controversial. Litigators may find themselves faced with conflicts between believer and nonbeliever expert opinion on the value of attempting to analyse which joints might benefit from injection therapy.

PRACTICE POINT

Possible characteristics of facet joint origin of Low Back Pain:
1. WELL-RELIEVED BY RECUMBENCY
2. age >65 years
Not worsened
3. by coughing
4. by (backward) hyperextension
5. by forward flexion
6. when rising from flexion
7. extension-rotation

Clinical methods for identifying clients with injured facet joints are improving. There are no unequivocal findings on history or examination, but a recent French paper ⁴ proposed that over 90% of responders and 80% of nonresponders to a single injection of local anesthetic can be predicted if relief after lying recumbent is accompanied by at least 4 out of 6 other features.

The authors caution that these features are not proven as characteristic of facet joint disease, but suggest that they provide a sound basis for further empirical research.

Australian researchers ⁵ found that response to initial injections of short-acting local anesthetic (xylocaine) at one or more joints occurred in half the patients in their series, but that only 15% benefitted from a subsequent longer acting injection (bupivacaine).

Belgian radiologists, using unequivocal response to a single injection as a yardstick, were able to identify characteristic patterns of abnormality ⁶ on conventional (non-computed) tomography of facet joints.

PRACTICE POINT

Facet joints are showing promise as a missing piece of the jigsaw of cervical whiplash as well as Low Back Pain

Facet joint biomechanics in rear end collisions was a major topic at the February, 1999 World Congress on Whiplash-Associated Disorders. Once the papers are published, we will review them in a major digest in Personal Injury News, Volume 5.